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The epoxy injection method can be used to repair concrete cracks based on its width, length, and depth. The procedure used to inject epoxy into the cracks may vary depending on the location and direction of the cracks.

This article explains the general procedure and recommendations to repair the concrete cracks using epoxy.

Recommended Applications of Epoxy for Concrete Cracks

  • Epoxy should be used for cracks that can be completely fixed, and not for structures that are likely to be subjected to continuous movement and crack formation.
  • Structural cracks and cracks with larger depth must not be repaired using epoxy. Such cracks require individual supervision from engineers.
  • Epoxy cannot be used to repair cracks formed due to corroded steel as the metal continues to undergo corrosion even after filling with epoxy.

Epoxy to Fill Concrete Cracks

The procedure to fill the concrete cracks using epoxy involves the following steps:

  1. Preparation of concrete surface
  2. Installation of ports
  3. Injection of epoxy crack

1. Preparation of Concrete Surface

1. Start the procedure by cleaning the cracked concrete surface. Clean the crack area extending to half-inch on either side of the crack. This extra area is necessary to have the bonding of epoxy with the existing concrete surface.

2. The area can be cleaned either using a wire brush or a high-pressure water jet.

3. After cleaning, the area should be allowed to dry. The process can be sped up using air-dryers.

4. Do not use mechanical tools as they create additional debris.

5. Ideally, when the cracks are not wide enough to repair, they are widened into a V-shape. A V-shaped crack helps to generate more resistant finishing.

2. Installation of Ports

1. Ports serve as the entry for epoxy into the cracks and eliminate the need for drilling. A minimum of two ports are installed during a single injection of epoxy.

Fixing Ports over Concrete Cracks
Fixing Ports Over Concrete Cracks

2. The ports are installed with proper spacing for injection at appropriate locations.

3. After installing the ports, seal the top of the crack using an epoxy paste. This is applied along the crack length. This paste dries up within 30 minutes.

4. The paste applied must stay as such when the ejection process is performed.

5. The epoxy paste seal is affected by the change in temperature of the concrete.

Sealing the Crack Surface Before Epoxy Injection
Sealing the Crack Surface Before Epoxy Injection

3. Injection of Epoxy into Concrete Cracks

1. Start injecting the epoxy from the lowest part and continue the process till the epoxy fills the cracks and comes out of the next port. 

Injection of Epoxy into the Cracks through Ports
Injection of Epoxy Into the Cracks Through Ports

2. While filling horizontal cracks, close the second port to facilitate deeper penetration of epoxy into the concrete cracks.

3. Repeat the process until no more epoxy comes out and then remove the cartridge.

4. Move on to the next open port or the port from which epoxy comes out. After moving the port forward, repeat the injection process.

5. Inject the epoxy into the crack with uniform pressure. This practice helps with the adequate flow of epoxy without leaving voids.

6. After completing the process, remove the ports and the top seal from over the crack.

Tips for Epoxy Crack Repair Works

Some important tips for performing neat epoxy injection repair process are:

  1. Start the injection process with a lower pressure, and with time, the pressure can be increased as required.
  2. High epoxy injection pressure is required for larger cracks.
  3. Fill large and wide cracks slowly to ensure that the epoxy completely fills the cracks.
  4. The outer epoxy seal can be removed after the entire injection process, using a chisel or scraper.
  5. In the case of discontinuous cracks, there are chances for the backflow of epoxy. Always check for such issues during the injection process.
  6. If there is a leak in the top seal, fill it using a crayon. This is recommended only for small leaks.
  7. The ports must be maintained at least for two days. This is to ensure that the concrete crack is sealed.
  8. When the crack is large, an epoxy injection may not work. Always check this and then proceed with the injection process.

FAQs

What are the steps to inject epoxy into concrete cracks?

The procedure to fill the concrete cracks using epoxy involves the following steps:
1. Preparation of concrete surface
2. Installation of ports
3. Sealing the crack surface
4. Injection of epoxy through the ports

What are the tips followed for epoxy crack repair works?

Some important tips for performing neat epoxy injection repair process are:
1. Start the injection process with a lower pressure, and with time, the pressure can be increased as required.
2. High epoxy injection pressure is required for larger cracks.
3. Fill large and wide cracks slowly to ensure that the epoxy completely fills the cracks.
4. The outer epoxy seal can be removed after the entire injection process, using a chisel or scraper.
5. In the case of discontinuous cracks, there are chances for the backflow of epoxy. Always check for such issues during the injection process.
6. If there is a leak in the top seal, fill it using a crayon. This is recommended only for small leaks.
7. The ports must be maintained at least for two days. This is to ensure that the concrete crack is sealed.
8. When the crack is large, an epoxy injection may not work. Always check this and then proceed with the injection process.

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Neenu Arjun

Neenu Arjun

EDITOR
Neenu is a Civil and Structural Engineer and has experience in Design of Concrete and Steel Structures. She is an Author, Editor and Partner at theconstructor.org.

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